As long as you are using Carter 3 step AVS rods, you are correct, the top does not need to come off the carb. As simple as different spring pressure could help solve the problem also. Stiffer springs (different color) will make it harder for his existing rods to get sucked fully down into the jet under high vacuum (making the mixture richer).
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph